Computers may be equipped with a real time clock (“RTC”) that is used to provide current time and date information to a user. More specifically, a RTC generally refers to a clock that is independent of the perations of the computer on which the clock runs, and that therefore must be able to track a current time even when the computer is turned off, in a power-saving mode, or performing other processing. The RTC thus provides a computer user with the familiar and convenient experience of viewing the current date and time, e.g., while using the computer. Further, the RTC may be used to provide software applications that rely on a knowledge of a current date and time, such as, for example, calendar and/or appointment applications.
A RTC may provide, for example, year, month, week, hour and second information. In so doing, the RTC may include, or rely on, a periodic pulse signal, as well as a state mechanism or counter that may be used to track/count transitions of the periodic pulse signal between states. For example, a Central Processing Unit (CPU) may be used to monitor transitions between states of the RTC.
As referenced above, however, the RTC should operate accurately even when the computer is off or in a low-power mode. For example, some computing devices may periodically enter a low power mode, in order to conserve battery life. However, the computing device (e.g., for the CPU of the computing device) may be unable to monitor the incoming RTC signal when in a low power mode. Consequently, the computing device (e.g., CPU) may be required to ‘wake up’ or enter a normal operating mode in order to track the incoming RTC signal in an accurate manner. Thus, a benefit of the low power mode may be lost or reduced, e.g., battery life for a battery of the computing device may be spent that could otherwise be conserved. In other words, competing needs exist to minimize power consumption (and thereby maximize battery life) on the one hand, and to maximize RTC accuracy on the other hand.